ABSTRACT

We report theoretical and experimental investigations on the structures of strontium and magnesium oxalates, and corresponding Raman spectra at high pressure. These systems have shown progress in the generation of CO₂ and in the synthesis of energetic doped polymeric carbon monoxide after X-ray irradiation and simultaneous application of high pressure. Density functional perturbation theory (DFT) was used to calculate the zone center optical phonons in monoclinic and triclinic strontium oxalate, and the ambient triclinic phase of magnesium oxalate. Vibration modes were also determined in terms of atomic displacements for both compounds. The simulations were compared to experimental Raman spectra in an effort to elucidate the details of the phase transition between monoclinic and triclinic phases. Additional phonon dispersion calculations of the compounds were performed to gain better insight into the dynamic phase stability in strontium and magnesium oxalates under high pressure.

摘要

我们报告了锶和草酸镁的结构以及在高压下相应的拉曼光谱的理论和实验研究。这些系统已显示出CO ₂产生的进展X射线照射和同时施加高压后，在高能掺杂的聚合一氧化碳的合成中。用密度泛函微扰理论（DFT）计算了单斜晶和三斜草酸锶中的区域中心光子，以及草酸镁的三斜相。还根据两种化合物的原子位移确定了振动模式。为了阐明单斜晶相和三斜晶相之间的相变细节，将模拟与实验拉曼光谱进行了比较。对化合物进行了额外的声子色散计算，以更好地了解锶和草酸镁在高压下的动态相稳定性。